1. Field of the Invention
The present invention relates to a coil form for supporting coils of wire, for example, of an antenna coil, and to a coil. The antenna coil is useful for transmitting or receiving electronic signals.
2. Description of the Related Art
A known coil form 10 is illustrated in FIG. 1. The known coil form 10 is shaped like a cube having square sides 12, three of which are illustrated in FIG. 1. Three coils of wire (not illustrated) are wrapped in three orthogonal directions around the cubic coil form 10. Each coil is shaped like a square by the cube form. The coils overlap where they intersect.
Posts 16, which serve as terminal posts for the ends of the coils, extend outwardly from the corners 14 of the coil form 10. Since each wound coil has two ends, there are six posts 16. The wound coils and the coil form are usually disposed in an enclosure or housing. The known coil form 10 wastes space in the enclosure because the posts 12 extend outward from the corners 16 and this must be accommodated in the enclosure, which reduces the maximum cross-section for the coil in any size enclosure.
In general, the effective winding area of a coil of wire is the product of the number of turns of wire within the coil multiplied by the area surrounded by the coil. When the number of turns is selected, the effective winding area of a coil is only a function of its area. Thus, when the greatest exterior dimensions of a coil (i.e., its overall width) cannot be changed, and when the number of turns cannot be changed, the effective winding area of the coil is determined by its shape.
The square shape of the coils supported by the known coil form 10 is disadvantageous because it limits the effective winding area of the coils, with respect to the greatest external dimensions of the coil form 10 (i.e., the distance between opposite corners 14), in any enclosure.